In recent years, the importance of projecting units used for presentations at conferences, in which a large number of participants take part, etc. has increased. When a projector is used, the presenter prompts the participants to refer to an image projected onto a screen and explains contents of the image. An obstacle, such as a person or an object, that blocks the projected image may appear between the projector and the screen. For example, if the presenter stands in front of the screen to give an explanation, the presenter himself/herself becomes an obstacle. If there is an obstacle that reflects light (such as a PC or a plastic bottle), the light is reflected in a direction different from a projection direction of the projecting unit.
The presenter, when he/she is an obstacle, directly receives light from the projecting unit in his/her eyes or light reflected by an obstacle that reflects light is directly received in eyes, which is not desirable. For this reason, a technology has been proposed in which, when a person or an object enters a projection area, the projection light is reduced or blocked (Patent Document 1: Japanese Patent No. 3630015, Patent Document 2: Japanese Patent No. 4366631).
However, information on a position of a person is detected from image information in the technology disclosed in Patent Document 1 and this technology has a problem in that, in a projector system, it is extremely difficult to distinguish, when the projected image contains a person, a projected image and an actual presenter, etc., and thus the accuracy with which a person is extracted is low.
In the technology disclosed in Patent Document 2, a process of detecting entry into the projection area using infrared light and a process of reducing or blocking the projection light are performed. However, this technology cuts all the projection light, which leads to a problem in that projection at a part irrelative to the entering person also stops.
The present invention has been made in view of the above. An object of the present invention is to provide a highly accurate and effective anti-dazzle function.